However the current situation is worrisome, because alternative implementations are dying and in the case of the web, diversity is important.
Both Opera and Microsoft's Edge are now powered by Chromium. Chromium is a project controlled by Google. Its redeeming quality, in terms of its open source nature, is the ability to fork, however competitors such as Microsoft proved that they no longer have the capacity to develop a modern browser.
At this point the only remaining alternatives are Firefox and Safari.
I think nowadays Firefox is a much better browser and that Mozilla is better at guarding my interests, so I would use Firefox even if it weren't a better browser, however the market isn't necessarily interested in that.